condition mean min max ZT0-3 2.4574999999999996 2.2212199999999998 2.69378 ZT4-7 3.39504 3.39504 3.39504 ZT8-11 2.62807 2.62807 2.62807 ZT12-15 0 0 0 ZT16-19 4.07882 4.07882 4.07882 ZT20-23 4.565565 4.565565 4.565565